The present invention relates to a harvester and a flail trimmer for large bulbous onions which also can be a used on similarly shaped root crops such as turnips, parsnips and rutabagas. More particularly, the inventionxe2x80x94in one aspectxe2x80x94comprises the steps of withdrawing the onions from earth after rough cutting their foliage tops and roots, conveying them up an incline to a cleaning station and thence to a first location where bothxe2x80x94surprisinglyxe2x80x94remaining foliage tops and roots are serially trimmed by tumbling them over a series of rotating and caged flail drum sub-assemblies which then deposits them in a surprisingly enhanced trimmed state at a second location spaced a lineal distance from the first location. In accordance with another aspect, the series of caged, rotating flail drum sub-assemblies of the invention each includes independently rotating cylindrical cage circumferenential of a series of transverse knives mounted on a central , independently driven shaft. The cylindrical cage includes a side wall provided with a plurality of slots defining major axes of symmetry that are substantially transverse to axis of rotation of the central driven shaft. When remaining tops or roots penetrate the slots, only the tip portions of the knives are adapted to contact the tops or roots at a selected, constant radial distance from the axis of rotation of the central shaft thereby creating a maximum cutting solid of rotation for such knives. Result: a surprising rapid harvesting and trim rate.
Experience has shown a plethora of harvester and trimmers for use in harvesting and trimming vegetables. One such apparatus is described in U.S. Pat. No. 4,182,420 for xe2x80x9cROOT CROP HARVESTER AND TRIMMERxe2x80x9d in which a series of endless belts are stacked above and below a orienting zone which positions the roots of the crop, viz., carrots, in positions normal to a particular set of belts whereupon trimming knives trim in a plane parallel to the plane of the belts. Another apparatus is described in U.S. Pat. No. 5,431,231 for xe2x80x9cHARVESTER FOR ROOT VEGETABLESxe2x80x9d in which the roots are trimmed after being gathered by a crawler type harvester by a stalk cutter after being correctly oriented by a pair of guide discs. In these apparatuses both foliage tops and tops are not trimmed. Still another apparatus is described in U.S. Pat. No. 3,989,110 for xe2x80x9cGREEN ONION HARVESTERxe2x80x9d in which the lower leaves of the green onions are removed by bruising them between sets of belts after the green onions are removed from the soil using a plurality of blades. Such an apparatus is not suitable for use in harvesting and trimming large bulbous onions.
In many parts of the country, onions have been successfully harvested by machine for some time. Although many attempts have been made to mechanically harvest the short-day onions grown in the southern U.S., primarily in south Texas, none has yet proven acceptable to the growers and shippers. These onions are usually planted in the early Fall, grow over the mild southern winter, and are ready for harvest early in the Spring. At harvest time the onions still have actively growing green tops, although some of them may have fallen down, and a robust root system. In addition, these short-day onions are harvested at a time when they are rather low in solids, and thus are more susceptible to bruising and mechanical damage than onions grown in northern locations which are harvested in Summer and early Fall.
The Federal Specifications for shipping onions require that 90% of the roots and tops be trimmed within one inch of the bulb of the onion. To meet these specs, hand crews are utilized to pull and clip the onions. This is arduous and tiring work, especially on those afternoons in the Spring that top out in the upper 90s Fahrenheit. For this and other reasons, it is becoming increasingly difficult for the growers to assemble crews large enough to meet the rapid harvesting schedule of these short day onions.
Thus there is incentive for growers to consider the possibility of harvesting their onions by machine. The difficulty of mechanically trimming the green tops and heavy root systems of these short-day onions to meet these Federal Specifications has been the major challenge in developing a mechanical harvester. The present invention meets and overcomes that challenge.
In addition to the prior art previously mentioned, note these additional attempts of which I am aware to trim tops and roots of onions which fall into three broad categories.
1. A conveying system which lifts the onions out of the ground and conveys them under a vacuum with sufficient strength to lift the tops upright while the weight of the onions holds them down against the conveyor. Immediately behind the vacuum is a sickle cutter which cuts the tops off and blows them back onto the field, leaving the onions to remain on the conveyor where they are delivered to other conveyors for hand sorting and then loading into trailers being pulled alongside the harvester.
This system has some major drawbacks. (a) The length of the cut tops is quite random. (b) Often smaller onions will be sucked up too high and be torn up by the sickle cutter. (c) And the roots are not trimmed at all. (d) Some of the green tops would be heavy enough that they would not be picked up at all.
2. A system where onions are delivered to a flat table that may have a slight tilt to it and/or may be vibrating to urge the onions to move along in the desired direction. The table will have a series of holes, approximately 1-xc2xd inches in diameter, through which the roots and tops will protrude from time to time. Underneath this table, and in close proximity to its underneath side will be a series of rotating knives, like power lawnmower blades. When the roots or top of an onion protrude(s) through a hole which is over the cutting edge of one of the knives it will be cut off.
The limitations of this system are (a) Inefficient use of the surface area of the table. Assuming a 30 inch diameter blade with 3 inches of cutting edge at the tips, and fitting the maximum number of 1.5 inch diameter holes in the table over the area swept by those cutting edges, only 19% of the table area is available for trimming. Using 15 inch diameter blades with 3 inch cutting edges (a generous assumption) the area of the table where trimming can occur only increases to 33%. (b) When onions pass over this trimming table en masse, as they should to achieve adequate throughput, they often are pushed along without tumbling. When they don""t tumble there is no opportunity for the roots or tops to stick through the holes and get trimmed off. Some experimenters have partially overcome this problem by hanging oscillating rubber fingers over the onions to urge them to tumble across the table. (c) Much of the cut plant material builds up on the structure that is required beneath the table to support the motors or pulleys that drive the blades.
3. A system similar to number 2 above with 1.5 inch wide slots in the table, running parallel to the direction the onions are traveling, instead of the 1.5 inch diameter holes. The same limitations apply, however.
In a field harvester and trimmer for root crops having foliage tops growing from the crowns of the crop to be harvested and trimmed, such as large bulbous onions, turnips, parsnips and rutabagas, consisting of a movable vehicle having at least a forward mounted severing and lifting mechanism and trimmer, the improvement comprising a series of rotating and caged flail drum sub-assemblies for trimming the foliage tops and roots of the gathered crop the results of which is a surprisingly enhanced trimmed state. In accordance with the invention, the series of caged, rotating fail drum sub-assemblies of the invention each includes independently rotating cylindrical cage circumferenential of a series of transverse knives mounted on a central, independently driven shaft. The cylindrical cage includes a side wall provided with a plurality of slots defining major axes of symmetry that are substantially transverse to axis of rotation of the central driven shaft. When remaining tops or roots penetrate the slots, only the tip-portions of the knives are adapted to contact the tops or roots at a selected, constant radial distance from the axis of rotation of the central shaft thereby creating a maximum cutting solid of rotation for such knives. Result: a surprisingly rapid harvesting and trim rate.